In order to optimize crop yields it is generally necessary to provide for uniform distribution of planting materials such as seeds or fertilizers. Seed distributors today commonly utilize a seed supply in communication with an air blower for providing an air-entrained stream of seeds to a distribution apparatus wherein the seed stream is divided into a plurality of smaller air-entrained seed streams. The smaller seed streams are then conveyed to the ground by corresponding tubes which discharge the seeds behind furrow openers and into furrows as the implement advances.
Specific prior practices include the use of vertical distribution apparatuses which divide an upwardly conveyed air-entrained stream of seeds into a horizontal layer of tube outlets that encircle the upper end of the apparatus. Prior horizontal distribution apparatuses have typically effected distribution across a generally flat layer of tube outlets by relying on some sort of internal bafflelike structure such as mechanical vanes or conical obstructions.
The cited prior practices have a number of problems or shortcomings. The vertical distribution apparatuses require a relatively large volume of air flow per unit of seed carried in order to overcome gravitational forces and deliver the seeds up to the tube outlets. Furthermore, the vertical distribution apparatuses, by projecting upwardly for a considerable distance above the level of the planting frame, can present serious obstructions when the planting frame includes hinging wing-type sections which fold up for transport. The internal structures of prior horizontal distribution apparatuses result in increased drag on the air stream and therefore can require additional power consumption and air flow per unit seed distributed. Furthermore, those apparatuses that have adjustable mechanical vanes can be difficult to properly adjust and as a result can provide a non-uniform distribution of seeds.
Consequently, a need exists for improvements in distribution apparatuses that will result in a uniform distribution of seeds while minimizing power and air flow requirements.